Aim: The aim of the study was objective morbidity comparison of the open and laparoscopic colorectal surgery using the recalibrated POSSUM scoring system, taking into account potential „case mix“ of samples. Material and Methods: In total 510 patients participated in the study, undergoing an elective colorectal surgery between 1st January 2001 and 31st January 2004. The samples of patients were operated either by an open or laparoscopic technique were compared. The study was retrospective-prospective, non-randomized. The basic data of the patient, data of the POSSUM scoring system (physiological score, operative score), data describing the surgery, post-operative course and complications were monitored. The individual risk of morbidity was evaluated by the modification (recalibration) of the original model of the POSSUM for the sample of patients operated by the open technique. Recalibration was carried out by the method of logistic regression analysis and tested. The real morbidity in relation to the individual risk of patients in both samples was afterwards statistically analyzed. P-value < 0.05 was considered statistically significant. Results: The complete data were obtained from 274 patients operated by the open technique and 231 patients operated laparoscopically. Although it was not a randomized study, both samples were comparable in basic characteristics (sex, age, BMI, ASA classification, surgery localization, type of procedure). In the group operated by the open technique, the patients with a malignant disease were represented more often and there was also a higher portion of palliative surgeries. The samples did not differ significantly in operative time, blood loss or frequency of per-operative complications. As far as post-operative complications are concerned, the post-operative bleeding into the abdominal cavity was recorded more often with the group operated by the laparoscopic technique, while the group operated by the open technique exhibited a higher occurrence of cardiac, circulation and neurological complications. The mortality in the group operated laparoscopically did not significantly differ from the group operated by the open technique (3.5% resp. 3.3%), the morbidity was significantly lower in the laparoscopic group (27% resp. 39%). The original POSSUM model recalibrated by the logistic regression analysis confirmed its compactness with the starting data and coefficient significance. The statistical analysis of morbidity related to the individual risk groups derived by the modificated (recalibrated) POSSUM proved significantly lower morbidity with the patients operated laparoscopically (p < 0.05). Conclusion: The elective laparoscopic colorectal surgery is associated with lower post-operative morbidity than the open approach, including high-risk patients.

        Key words: laparoscopy – colorectal surgery – postoperative complications – morbidity – POSSUM score